Air quality issues after some recent attic HVAC work. Pics of work enclosed.

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Air quality issues after some recent attic HVAC work. Pics of work enclosed.

I recently had some HVAC work done in my attic to help alleviate higher temperatures in my second floor home office. As part of this process they installed a hot air return in my office, moved the office supply duct closer on the trunk to the air handler to supposedly increase air flow in office, and also added a return box for my returns to go into.

I have noticed since we have done this work that my kids and my allergies have been bad when we are upstairs and am concerned that maybe some of the unconditioned air from the attic is making it into AC. We already did a mold/indoor air quality test and that came up clean. Hell it could just be allergies, but I have never really had any.

So I went up into the attic and noticed some things that I want to make sure is right.

Where the office supply flex is attached to the main duct there is a stream of cold air being shot out into the attic. I know that shouldn't happen and needs to be fixed, but would that also pull in attic air? You can see a photo of this here:

I also see the return box, but not sure if its installed correctly. From what I can tell, they only moved the main upstairs heat return to the return box and connected my office return directly to the air handler. I didn't have much room in the attic to check that 100%. Should there be insulation around the return box. From what I have been told the all ducts are supposed to be insulated as per code, but am not sure if a repair needs to be done to code. An example picture is:

I also took out my office return filter and looked into it and noticed that part of the duct is inside the black plastic box, but a portion is not. Could this be sucking air in from wall voids? You can see what I am talking about in the picture below. Look inside the red circle.

Finally, I see on one side of the return grill black plastic box that I see dry wall through some of the holes. Should the black plastic box lip have gone down further to cover any wall gaps? Not sure if this matters or not, but you can see what I am talking about in this picture.

ugh...cellulose insulation.
think about this...when they cut the hole for the new supply duct, cellulose particles
fell inside the house. cellulose is ground newspaper treated for with borate.
it makes a very fine 'dust' that enters the house through every unsealed hole.
and they just made new holes.

because you can't seal around supply boxes on all sides from the attic..
esp with cellulose,
I've learned to do it from inside the house.
see attached picture.

I use Hardcast brand #1402 mastic tape. not the stuff they used on
your new duct...mastic tape...1402 hardcast.

sealing supply boxes to sheetrock as in the pic is the only way
I've found that lasts and holds the box tightly in place
when supply grill is re-installed.

1402 will seal all of the areas you mention as long as surfaces
are clean & dry.
check inside returns...take your existing supply grills down &
seal all of these supply boxes too.

the house I'm currently working in has cellulose & a child
with asthma. today I shop vac'd half a bag of cellulose out of
the return air.

sealing supply & return leaks is in your best interest.

best of luck.

Attached Images

The cure of the part should not be attempted without the cure of the whole. ~Plato